They didn't need telling twice. Within a second, the three of them were bolting for the doorway and running down the narrow staircase they had come up, into the maze of corridors that waited below. The screen in the room above was still slowly counting their time, coming closer to the two minute mark, the Doctor keeping track of the countdown mentally.

Leaving the stairs far behind, they were weaving their way through the maze of interweaving corridors, Amy and Rory following the Doctor, who seemed to give the impression he knew the way. They ran down the corridor, past the room that had contained the crack, turning a corner, then another. They could all practically hear the countdown ticking away, counting away the seconds they had left to live. Rounding another corner, they ran at full speed down another corridor, the Doctor never stopping, never stumbling, doing what he was used to doing – running for his life.

Another corner, the Doctor turned sharply, Amy and Rory having to slow down slightly to follow his unpredictable movements. Within a few seconds, they were on the home stretch, the main corridor becoming visible ahead of them. The Doctor practically leapt into it, Amy and Rory close behind.

"Er, Doctor…" Rory began. But the Doctor had already seen it. The shroud of Vashta Nerada, sat in silent patience at the end of the corridor.

"Keep moving!" the Doctor yelled, running from the now fast-moving curtain of shadows. At the far end of the long hallway, there was now a door-shaped hole once again where the wall had originally grown over the doorway. "Default settings." the Time Lord commented under his breath as he ran through, heading down the next staircase, Amy following him and Rory close behind her.

"Doctor, that creature-" Amy began, remembering the hideous beast that had attacked them on this floor.

"Was a creation of the Nightmare Children! With them gone, it's gone!" the Doctor finished, his tone as hurried as his footsteps. The floor was easy to cover without the monster pursuing them. They ran across the open space, only occasionally having to dodge a wooden pillar.

In his mind's eye, the Doctor could still see time ticking away. They would have less than a minute now. He led Rory and Amy through a door – they were taking a different route to the one they had used to reach this floor. It would take far too long to cover those long, isolated corridors again. Behind the door, they found a shorter corridor leading to the house's main staircase – the one that would lead them to the entrance hall.

"Come along Ponds!" the Doctor yelled back, aware of the ever-growing distance between him and his companions.

BANG!

A section of the ceiling above them had collapsed, a torrent of dust being thrown across them. The white lightning they had seen in the control room was spreading, becoming visible throughout all the corridors. Vibrations from the upcoming explosion were tangible throughout the entire building now, and becoming heavier with every second. The Doctor, Amy and Rory were all struggling to stay on their feet, the vibrations becoming more of a miniature earthquake, as they clambered over the pile of rubble that was once ceiling. The staircase was just ahead of them.

Ten seconds, the Doctor thought, as he leapt from the carpeting of the corridor to the narrow surfaces of the steps, landing a little ungracefully on them. Amy and Rory were there, racing into the entrance hall. A clutter of now lifeless butler statues filled the room, a reminder of the past threat.

Five seconds.

"Come on!" the Doctor ordered, the front door now in sight.

Three.

They couldn't make it. Only the Doctor had been keeping track of time, but the rocking of the house and violent flashes of lightning were now so severe that they could all tell there was no way they would reach the door in time.

Two.

The wooden black door just ahead, just out of reach. No time to sonic. Just one last hope…

One.

"GERONIMO!"

The Doctor threw himself forwards Amy and Rory leaping wildly into the air. The explosion was titanic. It burst out of every wall of the building, bathed in scorching flames, sweltering heat and blinding light. The shockwave propelled the time travellers through the air, the door ahead of them blown clean off its hinges. Thick tides of dust were drowning all clarity from the air, choking the Doctor and his companions as they leapt through the building's obliteration, rolls of black smoke blinding them…

The clouds of destruction seemed to disappear, parting from the bodies of the two humans and the Time Lord. The trio burst through the smokescreen, landing a few feet in front of it, flat on the dead grass that rested atop Elm Hill. The last swathes of smoke and flames faded, the house destroyed. It was over.